Publications

Global warming and melting of the ice on both poles of the Earth is caused by the greenhouse effect which is the result of CO₂ production. This gas is considered as the main gas causing the greenhouse effect although not the only one. To reduce the total amount of CO2 emitted to the atmosphere mankind looks for an alternative fuel with no carbon present in its molekules. Hydrogen is such a fuel although emissions are produced also during the fuel production process. To compare hydrogen fuel with fossil fuels more aspects have to be considered.

Direct Numerical Simulation (DNS) data obtained by Dave and Chaudhuri (2020) from a lean complex-chemistry hydrogen-air flame associated with the thin-reaction-zone regime of premixed turbulent burning are analyzed to perform a priori assessment of predictive capabilities of the flamelet approach for evaluating mean species concentrations. For this purpose dependencies of mole fractions and rates of production of various species on a combustion progress variable c obtained from the laminar flame are averaged adopting either the actual Probability Density Function (PDF) P (c)  extracted from the DNS data or a common presumed β-function PDF. On the one hand the results quantitatively validate the flamelet approach for the mean mole fractions of all species including radicals but only if the actual PDF P (c) is adopted. The use of the β-function PDF yields substantially worse results for the radicals’ concentrations. These findings put modeling the PDF P (c) on the forefront of the research agenda. On the other hand the mean rate of product creation and turbulent burning velocity are poorly predicted even adopting the actual PDF. These results imply that in order to evaluate the mean species concentrations the flamelet approach could be coupled with another model that predicts the mean rate and turbulent burning velocity better. Accordingly the flamelet approach could be implemented as post-processing of numerical data yielded by that model. Based on the aforementioned findings and implications a new approach to building a presumed PDF is developed. The key features of the approach consist in (i) adopting a re-normalized flamelet PDF for intermediate values of c and (ii) directly using the mean rate of product creation to calibrate the presumed PDF. Capabilities of the newly developed PDF for predicting mean species concentrations are quantitively validated for all species including radicals.

As the global electricity systems are shaped by decentralisation digitalisation and decarbonisation the World Energy Council’s Innovation Insights Briefs explore the new frontiers in energy transitions and the challenges of keeping pace with fast moving developments. We use leadership interviews to map the state of play and case studies across the whole energy landscape and build a broader and deeper picture of new developments within and beyond the new energy technology value chain and business ecosystem.<br/><br/>With major decarbonisation efforts and the scaling up of renewable power generation the widespread adoption of energy storage continues to be described as the key game changer for electricity systems. Affordable storage systems are a critical missing link between intermittent renewable power and a 24/7 reliability net-zero carbon scenario. Beyond solving this salient challenge energy storage is being increasingly considered to meet other needs such as relieving congestion or smoothing out the variations in power that occur independently of renewable-energy generation. However whilst there is plenty of visionary thinking recent progress has focused on short-duration and battery-based energy storage for efficiency gains and ancillary services; there is limited progress in developing daily weekly and even seasonal cost-effective solutions which are indispensable for a global reliance on intermittent renewable energy sources.

The use of clean hydrogen is likely to form a key part of a net-zero emissions future and has the potential to replace natural gas for end use heating. As part of BDR Thermea Group Baxi Heating UK are at the forefront of hydrogen boiler development. Working with the Hy4Heat programme hydrogen fuelled boilers have been produced for inclusion in trial sites across the UK. This presentation will explore progress to date together with the hydrogen-ready boiler concept.

Alloying and structural modification are two effective ways to enhance the hydrogen storage kinetics and decrease the thermal stability of Mg and Mg-based alloys. In order to enhance the characteristics of Mg₂Ni-type alloys Cu and La were added to an Mg₂Ni-type alloy and the sample alloys (Mg₂₄Ni₁₀Cu₂)_100−xLa_x (x = 0 5 10 15 20) were prepared by melt spinning. The influences of La content and spinning rate on the gaseous and electrochemical hydrogen storage properties of the sample alloys were explored in detail. The structural identification carried out by XRD and TEM indicates that the main phase of the alloys is Mg₂Ni and the addition of La results in the formation of the secondary phases LaMg₃ and La₂Mg₁₇. The as-spun alloys have amorphous and nanocrystalline structures and the addition of La promotes glass formation. The electrochemical properties examined by an automatic galvanostatic system show that the samples possess a good activation capability and achieve their maximal discharge capacities within three cycles. The discharge potential characteristics were vastly ameliorated by melt spinning and La addition. The discharge capacities of the samples achieve their maximal values as the La content changes and the discharge capacities always increase with increasing spinning rate. The addition of La leads to a decline in hydrogen absorption capacity but it can effectively enhance the rate of hydrogen absorption. The addition of La and melt spinning significantly increase the hydrogen desorption rate due to the reduced activation energy.

From a permeability and selectivity perspective supported thin-film Pd–Ag membranes are the best candidates for high-purity hydrogen recovery for methane-hydrogen mixtures from the natural gas grid. However the high hydrogen flux also results in induced bulk-to-membrane mass transfer limitations (concentration polarization) especially when working at low hydrogen concentration and high pressure which further reduces the hydrogen permeance in the presence of mixtures. Additionally Pd is a precious metal and its price is lately increasing dramatically. The use of inexpensive CMSM could become a promising alternative. In this manuscript a detailed comparison between these two membrane technologies operating under the same working pressure and mixtures is presented.<br/>First the permeation properties of CMSM and Pd–Ag membranes are compared in terms of permeance and purity and subsequently making use of this experimental investigation an economic evaluation including capital and variable costs has been performed for a separation system to recover 25 kg/day of hydrogen from a methane-hydrogen mixture. To widen the perspective also a sensitivity analysis by changing the pressure difference membrane lifetime membrane support cost and cost of Pd/Ag membrane recovery has been considered. The results show that at high pressure the use of CMSM is to more economic than the Pd-based membranes at the same recovery and similar purity.

This report shows that low-carbon hydrogen supply at scale is economically and environmentally feasible and will have significant societal benefits if the right localised approach and best-practices for production are used. The report also demonstrates that there is not one single hydrogen production pathway to achieve low lifecycle greenhouse gas (GHG) emissions but rather the need for a fact-based approach that leverages regional resources and includes a combination of different production pathways. This will achieve both emission and cost reductions ultimately helping to decarbonize the energy system and limit global warming.

In 2020 more than 15 countries launched major hydrogen plans and policies and industry players announced new projects of more than 35GW until 2030. As this hydrogen momentum accelerates it is increasingly clear that decision makers must put the focus on decarbonization to ensure hydrogen can fulfil its potential as a key solution in the global clean energy transition making a significant contribution to net zero emissions. To support this effort the two-part Hydrogen Council report provides new data based on an assessment of the GHG emissions generated through different hydrogen supply pathways and the lifecycle GHG emissions for different hydrogen applications (see report part 1 – A Life-cycle Assessment). In addition the report explores 3 hypothetical hydrogen supply scenarios to measure the feasibility and impact of deploying renewable and low-carbon hydrogen at scale (report part 2 – Potential Supply Scenarios).

The report outlines that there are many ways of producing hydrogen and although GHG emissions vary widely very high CO2 savings can be achieved across a broad range of different hydrogen production pathways and end-uses. For example while “green” hydrogen produced through water electrolysis with renewable power achieves the lowest emissions “blue” hydrogen produced from natural gas with high CO2 capture rate and storage can also achieve low emissions if best technologies are used and best practices are followed. Across eight illustrative pathways explored in the report analysis shows that if hydrogen is used significant GHG emission reductions can be made: as much as 60-90% or more compared to conventional fossil alternatives. The study also looked into the gross water demand of hydrogen supply pathways. Water electrolysis has a very low specific water demand of 9 kg per kg of hydrogen compared to cooling of thermal power plants (hundreds of kg/kg) or biomass cultivation (hundreds to thousands of kg/kg).

Furthermore low-carbon hydrogen supply at scale is fully achievable. Having investigated two hypothetical boundary scenarios (a “green-only” and a “blue-only” scenario) to assess the feasibility and impact of decarbonized hydrogen supply the report found that both scenarios are feasible: they are not limited by the world’s renewables potential or carbon sequestration (CCS) capacities and they do not exceed the speed at which industry can scale. In the Hydrogen Council’s “Scaling up” study a demand of 21800 TWh hydrogen has been identified for the year 2050. To achieve this a compound annual growth rate of 30-35% would be needed for electrolysers and CCS. This deployment rate is in line with the growth of the offshore wind and solar PV industry over the last decade.

Hydrogen Council data released in January 2020 showed that a wide range of hydrogen applications can become competitive by 2030 driven also by falling costs of renewable and low-carbon hydrogen[1]. The new study indicates that a combination of “green” and “blue” production pathways would lead to hydrogen cost reductions relative to either boundary scenario. By making use of the near-term cost advantage of “blue” while also scaling up “green” hydrogen as the most cost-efficient option in many regions in the medium and long-term the combined approach lowers average hydrogen costs between now and 2050 relative to either boundary scenario.

Part 1 – A Life-cycle Assessment

• The life-cycle assessment (LCA) analysis in this study addresses every aspect of the supply chain from primary energy extraction to end use. Eight primary-energy-to-hydrogen value chains have been selected for illustrative purposes.
• Across the hydrogen pathways and applications depicted very high to high GHG emission reduction can be demonstrated using green (solar wind) and blue hydrogen.
• In the LCA study renewables + electrolysis shows strongest GHG reduction of the different hydrogen supply pathways assessed in this study with a best-case blue hydrogen pathway also coming into the same order of magnitude.

Part 2 – Potential Supply Scenarios

• Currently the vast majority of hydrogen is produced by fossil pathways. To achieve a ten-fold build-out of hydrogen supply by 2050 as envisaged by the Hydrogen Council in its ‘Scaling Up’ report (2017) the existing use of hydrogen – and all its many potential new roles – need to be met by decarbonized sources.
• Three hypothetical supply scenarios with decarbonized hydrogen sources are considered in the study: 1) a “green-only” renewables-based world; 2) a “blue-only” world relying on carbon sequestration; and 3) a combined scenario that uses a region-specific combination of green and blue hydrogen based on the expected regional cost development of each source.
• The study finds that a decarbonized hydrogen supply is possible regardless of the production pathway: while both the green and blue boundary scenario would be highly ambitious regarding the required speed of scale-up they do not exceed the world’s resources on either renewable energy or carbon sequestration capabilities.
• A combination of production pathways would result in the least-cost global supply over the entire period of scale-up. It does so by making best use of the near-term cost advantage of “blue” in some regions while simultaneously achieving a scale-up in electrolysis.
• In reality the decarbonized supply scenario will combine a range of different renewable and low-carbon hydrogen production pathways that are optimally suited to local conditions political and societal preferences and regulations as well as industrial and cost developments for different technologies.

You can download the full reports from the Hydrogen Council website

Hydrogen Council Report- Decarbonization Pathways Part 1: Life Cycle Assessment here

Hydrogen Council Report-Decarbonization Pathways Part 2: Supply Scenarios here

An executive summary of the whole project can be found here

As countries around the world rally behind net zero targets hydrogen is increasingly seen as a missing piece of the energy transformation puzzle to decarbonise harder-to-abate sectors. The possible pathway on which hydrogen might evolve still involves many uncertainties. With the growing momentum to establish a global hydrogen market comes the need for a deeper understanding of its broader effects including geopolitical aspects. IRENA has carried out an in-depth analysis of the geopolitics of hydrogen as part of the work of the Collaborative Framework on the Geopolitics of Energy Transformation (CF-GET). The report builds on IRENA’s substantial body of work in hydrogen and benefits from a wide range of expert input in the fields of energy and geopolitics.

This report considers whether and how hydrogen may disrupt future energy systems reflecting on many of the key themes discussed in the Global Commission’s report A New World – The Geopolitics of the Energy Transformation. The analysis offers insights into how countries and stakeholders can navigate the uncertainties and shape the development of hydrogen markets and outlines policy considerations to help mitigate the geopolitical risks and capitalise on opportunities. Some of the key findings of the report include:

• Hydrogen is part of a much bigger energy transition picture and its development and deployment strategies should not be considered in isolation.
• Setting the right priorities for hydrogen use will be essential for its rapid scale-up and long-term contribution to decarbonisation efforts.
• The 2020s could become the era of a big race for technology leadership as costs are likely to fall sharply with learning and scaling-up of needed infrastructure. Equipment manufacturing offers an opportunity to capture value in the coming years and decades.
• Hydrogen trade and investment flows will spawn new patterns of interdependence and bring shifts in bilateral relations.
• Countries with an abundance of low-cost renewable power could become producers of green hydrogen with commensurate geoeconomic and geopolitical consequences.
• Hydrogen could be an attractive avenue for fossil fuel exporters to help diversify their economies and develop new export industries.
• Supporting the advancement of renewable energy and green hydrogen in developing countries is critical for decarbonising the energy system and can contribute to global equity and stability.
• International co-operation will be necessary to devise a transparent hydrogen market with coherent standards and norms that contribute to climate change efforts meaningfully.

The effect of different cathodic potentials applied to the X70 pipeline steel immersed in acidified and aerated synthetic soil solution under stress using a slow strain rate test (SSRT) and electrochemical impedance spectroscopy (EIS) was studied. According to SSRT results and the fracture surface analysis by scanning electron microscopy (SEM) the steel susceptibility to stress corrosion cracking (SCC) increased as the cathodic polarization increased (Ecp). This behavior is attributed to the anodic dissolution at the tip of the crack and the increment of the cathodic reaction (hydrogen evolution) producing hydrogen embrittlement. Nevertheless when the Ecp was subjected to the maximum cathodic potential applied (−970 mV) the susceptibility decreased; this behavior is attributed to the fact that the anodic dissolution was suppressed and the process of the SCC was dominated only by hydrogen embrittlement (HE). The EIS results showed that the cathodic process was influenced by the mass transport (hydrogen diffusion) due to the steel undergoing so many changes in the metallic surface as a result of the applied strain that it generated active sites at the surface.

For liquid hydrogen (LH₂) to become an energy carrier in energy commodity markets at scales comparable to for instance LNG liquefier capacities must be scaled up several orders of magnitude. While state-of-the-art liquefiers can provide specific power requirements down to 10 kWh/kg a long-term target for scaled-up liquefier trains is 6 kWh/kg. High capacity will shift the cost weighting more towards operational expenditures which motivates for measures to improve the efficiency. Detailed exergy analysis is the best means for gaining a clear understanding of all losses occurring in the liquefaction process. This work analyses in detail a hydrogen liquefier that is likely to be realisable without intermediate demonstration phases and all irreversibilities are decomposed to the component level. The overall aim is to identify the most promising routes for improving the process. The overall power requirement is found to be 7.09 kWh/kg with stand-alone exergy efficiencies of the mixed-refrigerant pre-cooling cycle and the cryogenic hydrogen Claude cycle of 42.5% and 38.4% respectively. About 90% of the irreversibilities are attributed to the Claude cycle while the remainder is caused by pre-cooling to 114 K. For a component group subdivision the main contributions to irreversibilities are hydrogen compression and intercooling (39%) cryogenic heat exchangers (21%) hydrogen turbine brakes (15%) and hydrogen turbines (13%). Efficiency improvement measures become increasingly attractive with scale in general and several options exist. An effective modification is to recover shaft power from the cryogenic turbines. 80% shaft-to-shaft power recovery will reduce the power requirement to 6.57 kWh/kg. Another potent modification is to replace the single mixed refrigerant pre-cooling cycle with a more advanced mixed-refrigerant cascade cycle. For substantial scaling-up in the long term promising solutions can be cryogenic refrigeration cycles with refrigerant mixtures of helium/neon/hydrogen enabling the use of efficient and well scalable centrifugal compressors.